The present invention is directed to intraluminal catheters which are suitable for procedures such a percutaneous transluminal coronary angioplasty (PTCA) procedures.
PTCA is a widely used procedure for the treatment of coronary heart disease. In this procedure, a balloon dilatation catheter is advanced into the patient's coronary artery and the balloon on the catheter is inflated within the stenotic region of the patient's artery to open up the arterial passageway and increase blood flow through the artery. To facilitate the advancement of the dilatation catheter into the patient's coronary artery, a guiding catheter having a preshaped distal tip is first percutaneously introduced into the cardiovascular system of a patient by the Seldinger technique through the brachial or femoral arteries. The catheter is advanced within the selected artery until the preshaped distal tip of the guiding catheter is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from the proximal end, which extends out of the patient, to guide the distal tip of the guiding catheter into the ostium. A balloon dilatation catheter may then be advanced through the guiding catheter into the patient's coronary artery until the balloon on the dilatation catheter is disposed within the stenotic region of the patient's artery. The balloon is inflated one or more times to open up the arterial passageway.
One type of catheter frequently used in PTCA procedures is an over-the-wire type balloon dilatation catheter. Commercially available over-the-wire type dilatation catheters include the SIMPSON ULTRA LOW PROFILE.RTM., the HARTZLER ACX.RTM., the HARTZLER ACX II.RTM., the PINKERTON 0.018.TM. and the ACS TEN.TM. balloon dilatation catheters sold by the assignee of the present invention, Advanced Cardiovascular Systems, Inc. (ACS). When using an over-the-wire dilatation catheter, a guidewire is usually inserted into an inner lumen of the dilatation catheter before it is introduced into the patient's vascular system and then both are introduced into and advanced through the guiding catheter to its distal tip which is seated within the ostium of the desired coronary artery. The guidewire is first advanced out the seated distal tip of the guiding catheter into the desired coronary artery until the distal end of the guidewire extends beyond the lesion to be dilatated. The dilatation catheter is then advanced out of the distal tip of the guiding catheter into the patient's coronary artery, over the previously advanced guidewire, until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion to be dilatated. Once properly positioned across the stenosis, the balloon is inflated to a predetermined diameter with radiopaque liquid at relatively high pressures (e.g., generally 4-12 atmospheres) to dilate the stenosed region of a diseased artery. After the dilatation, the balloon is deflated so that the dilatation catheter can be removed from the dilated stenosis and blood flow will resume therethrough.
Fixed-wire type dilatation catheter systems are also utilized very frequently in PTCA procedures. This type of dilatation catheter has a guidewire or guiding member secured within the catheter and provides a low profile, i.e. small transverse dimensions, because there is no inner tubular member which is characteristic of a commercially available over-the-wire dilatation catheter. Commercially available fixed-wire dilatation catheters include the HARTZLER EXCEL.RTM., the HARTZLER LPS.RTM. and the SLALOM.TM. dilatation catheters sold by ACS.
Another type of dilatation catheter, the rapid exchange type catheter, was introduced by ACS under the trademark ACS RX.RTM. Coronary Dilatation Catheter. It is described and claimed in U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock) and U.S. Pat. No. 4,748,982 (Horzewski et al.) which are incorporated herein by reference. This dilatation catheter has a short guidewire receiving sleeve or inner lumen extending through a distal portion of the catheter. The sleeve or inner lumen extends proximally from a first guidewire port in the distal end of the catheter to a second guidewire port in the catheter spaced proximally from the inflatable member of the catheter. A slit may be provided in the wall of the catheter body which extends distally from the second guidewire port, preferably to a location proximal to the proximal end of the inflatable balloon. The structure of the catheter allows for the rapid exchange of the catheter without the need for an exchange wire or adding a guidewire extension to the proximal end of the guidewire. This catheter has been widely praised by the medical profession and it has met with much success in the market place because of the advantages of its unique design.
A recent improvement in the design and construction of fixed-wire dilatation catheters is disclosed in copending application Ser. No. 07/631,657 entitled FIXED WIRE CATHETER WITH ROTATABLE BALLOON ASSEMBLY which was filed on Dec. 21, 1990, and which is incorporated herein by reference. The fixed-wire catheter described in this copending application is provided with means to allow relative rotation between the balloon assembly and the core member of the guidewire so that the balloon will not wrap when the guidewire is torqued from its proximal end to guide the catheter as it is advanced through the patient's arterial system. This catheter design includes a sealing means which swells upon contacting the inflation liquid or other aqueous based liquids to prevent the passage of liquids through the seal. The structural integrity of the sealing means described in this reference depended to a large extent upon the core member or other inner member and this support usually precluded any significant longitudinal movement of the core member when the sealing means swelled in contact with an aqueous based liquid.
Another recent improvement in dilatation catheters is disclosed in copending application Ser. No. 07/809,888, filed Dec. 18, 1991, entitled INTRAVASCULAR CATHETER WITH MEANS TO SEAL GUIDEWIRE PORT, which includes a single lumen over-the-wire type catheter having a sealing means, such as a duck billed valve, on the distal end of the catheter and other locations thereon which seals against the guidewire or guiding member to prevent the loss of inflation liquid but which allows movement of the guidewire through the catheter in the same manner as in over-the-wire dilatation catheters. The single lumen is adapted to receive the guidewire and to direct inflation liquid to the interior of the dilatation balloon. The application is incorporated by reference into the present application.
What has been needed and heretofore unavailable is a sealing means which has adequate strength to be self supporting and to support a guidewire extending through the sealing means and which has sufficient lubricity to facilitate the movement of the core member or other inner member with respect to the dilatation balloon. The present invention satisfies these and other needs.